To facilitate the settlement with a user using a communication service, the service provider offers an account for each user exploiting the communication service. The user may deposit money into his or her account by dialing an access number provided by the operator or with the help of a work staff at a service center. When the user is exploiting a communication service, or after the user uses the communication service, the service provider may charge the fee for the service used by the user and charge the user account accordingly. The system for recharge service provided by the operator is called a voucher system. The voucher system includes one or more Voucher Centers (hereinafter VC). The VC stores information of a recharge card, for example, the number or status of the recharge card, etc. The status of the recharge card may be categorized into two types: valid status and invalid status. The valid status indicates that the recharge card has not been used for recharging and the card is within a valid period. The invalid status indicates that the recharge card has been used or the card is expired. Each recharge card has a key for identification. When the user is refilling the card, the key of the recharge card is required. The VC deposits the credit associated with the recharge card into the user account.
In a traditional intelligent network, the user account is stored in a Service Control Point (SCP) or a data service charging gateway. Generally, the data service charging gateway may do the rating and connect to the SCP to deduct the fee from the account. With the development of the telecommunication network, traditional intelligent network and data service charging gateway are evolving into an integrated charging system. In the evolved integrated charging system in the telecommunication network, the charging function is separated from a service control layer and a charging layer and is handled by a newly added network element, i.e., Online Charging System (OCS). Generally, the OCS has rating, charging, user account balance management and account management functions. The service control function which connects to and interacts with a service bearer layer may still remain in a network element in the service control layer. Currently, the user may recharge the account via an automatic recharge procedure by calling an access number or via a manual recharge procedure operated by a work staff at the service center. A conventional recharge procedure based on 3GPP network architecture mainly includes the followings. The SCP interacts with the VC to query for recharge card information. After the SCP passes the verification by the VC, the SCP interacts with the OCS and instructs the OCS to recharge via the recharge card associated with a recharge handling request. After the SCP receives a message indicating that the OCS has recharges the card successfully, the SCP interacts with the VC to instruct VC to set the recharge card and finally the SCP sends a recharge confirmation message to the OCS.
It is discovered that the above conventional recharge procedure encounters at least the following problems.
In the case where signaling loss or signaling timeout takes places in a signaling layer during the above recharge procedure (e.g., the SCP fails to receive an acknowledgement message indicating a successful recharge returned from the OCS within a predetermined time period or the SCP fails to send a recharge card setting request or the VC fails to set the recharge card and the SCP fails to receive the setting response message returned by the VC), the OCS has already completed the recharge for the user but the VC fails to set the recharge card in the above cases. The status of the recharge card in the VC still remains in a valid status which allows the recharge card to be used again. Consequently, this would bring huge loss to the operator.